Gliding sail



1966 w. c. BOLT 3,235,545

GLIDING SAIL Filed Feb. 5, 1965 2 Sheets-Sheet 1 v INVENTOR WILL/AM GBOLT NOV. 15, 1966 w. c. BOLT 3,285,545

GLIDING SAIL Filed Feb. 5, 1965 2 Sheets-Sheet 2 Z 'YNVENTOR j W/LL/AM 675011 BY 21% u. fiMW ATTORNEY United States Patent 3,285,545 GLIDING SAIL William C. Bolt, Burbank, Calif. (11335 El Merrie Dell Drive, San Fernando, Calif.) Filed Feb. 5, 1965, Ser. No. 430,580

Claims. (Cl. 244-138) This invention relates to a gliding sail to be used by a person or flyer in making a descent through the air from an aircraft and which may be utilized in winds exceeding twenty-five knots with greater safety than a parachute.

A primary object of the invention is to provide a gliding sail which is so constructed that it can be supported taut during flight to enable the flyer to effectively steer the sails course and thus have a choice of landing places over a wide area, especially where the flight is begun at a high altitude.

Another object of the invention is to provide a gliding sail Which is especially adapted for use in conjunction with a back parachute and a reserve parachute, for sport flying, and which is provided with means whereby the sail is held attached to the body of the user by the connected parachutes.

A further object of the invention is to provide a gliding sail having no rigid struts, braces, battens or airfoils.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, illustrating a presently preferred embodiment thereof, and wherein:

FIGURE 1 is a top plan view of the gliding sail with a flyer positioned thereon;

FIGURE 2 is an enlarged fragmentary longitudinal sectional view, taken substantially along the line 2-2 of FIGURE 1;

FIGURE 3 is an enlarged fragmentary sectional view, with certain parts omitted, taken substantially along a plane as indicated by the line 33 of FIGURE 1;

FIGURE 4 is an enlarged fragmentary plan view of one front corner of the sail;

FIGURE 5 is a cross sectional view thereof taken substantially along a plane as indicated by the line 5-5 of FIGURE 4;

FIGURE 6 is an enlarged fragmentary plan view of a portion of the central part of the sail;

FIGURE 7 is an enlarged plan view of one rear corner of the sail;

FGURE 8 is a sectional view taken along the line 88 of FIGURE 7 with a part of the flyers foot shown applied to the sail;

FIGURE 9 is an enlarged fragmentary sectional view taken substantially along the line 9-9 of FIGURE 1; and

FIGURE 10 is an enlarged fragmentary sectional view taken substantially along the line 1010 of FIGURE 1.

Referring more specifically to the drawings, the gliding sail in its entirety and compromising the invention is designated generally 12 and is constituted primarily by a rectangular piece of smooth flexible material 13, having high tensile strength, such as polyethylene terepthalate, marketed as Dacron or Mylar. The sail 12 includes a leading edge 14, a trailing edge 15, a right side edge 16 and a left side edge 17. The material 13 is cut out at the four corners of the sail 12, as seen at 18.

A strong flexible line 19 extends completely around the perimeter of the material 13 and is securely attached to each of the edges 14, 15, 16 and 17 in any conventional manner, as by being encased in a hem 20 of each edge, as seen in FIGURE 10. The line 19 has slack portions 21 disposed in the recessed corners 18.

As best seen in FIGURES 4 and 5, wooden inserts 22 are disposed in the slack line portions 21 at each of the two front corners 18 and have rounded or convex outer edges 23 each provided with a groove 24 in which a part of the slack line portion of said corner is received. The inserts 22 are secured within the slack line portions 21 by windings of plastic tape 25. The inserts 22, with the slack portions 21, of the two out out front corners 18 form handholds 26.

As best seen in FIGURE 7, a straight wooden insert 27 is disposed in the slack portion 21 of each rear cut out corner 18 and has an outer edge and ends provided with a continuous groove 28 in which said slack portion seats, for mounting the insert therein. The inserts 27 are secured to said last mentioned slack portions by additional windings of the tape 25 and combine therewith to form stirrups 29.

The material 13 has two elongated aligned openings 30 which are disposed transversely of the sail 12 and spaced from one another. A point midway between the openings 30 is located midway between the side edges 16 and 17, and said openings 30 are located somewhat nearer the leading edge 14 than the trailing edge 15. As best seen in FIGURES 3 and 6, each opening 30 is reinforced by two rigid plates 31 and two rubber washers 32. The washers 32 are disposed on opposite sides of the sail material 13 and between the plates 31, and said parts 31 and 32 are secured together by screw fastenings 33 which extend therethrough and are anchored in the plates. 31. The plates 31 have openings 34 and the washers 32 have openings 35, which openings correspond to and register with the openings 30. The washers 32 are of the same shape as the plates 31 but somewhat larger, so that the edges of the washers protrude beyond the edges of the plates to prevent the edges of the plates exerting a shearing action on the material 13, which would be likely to cause material to tear.

Each of the edges 14, 15, 16 and 17 is substantially uniformly bowed inwardly or concavely from end-to-end thereof, with the leading edge 14 recessed or bowed to a greater extent than the other edges. The material 13 is preferably perforated adjacent the leading edge 14 of the sail, as by means of two or more grommet-lined openings 36.

FIGURE 1 show a flyer 17 in a flying position on top of the sail 12, wearing on his back a parachute 38, which is attached to his body by a harness including shoulder straps 39 which extend from the parachute up over his shoulders and down the front part of his body. As is conventional, each shoulder strap 39 has a Dring 40 attached thereto. The Drings 40 are disposed at the front of the body adjacent the waistline and are spaced apart a distance corresponding to the spacing between the openings 30. The D-rings extend through the openings 30 and through the openings 34 and 35 which register therewith, .as seen in FIGURE 3. The D-rings 40 are attached to snap fasteners 41 of a conventional reserve parachute 42 which is thus attached to the flyer 37 and disposed on the underside of the sail 12. The D-rings 40 and snap fasteners 41 thus attach the sail 12 to the front of the body of the flyer near his waistline.

The flyers arms 43 are extended outwardly and forwardly with the hands 44 grasping the handholds 26, and the legs 45 are extended and spread with the balls of the shoe-encased feet 46 engaging the stirrups 29, to which the feet are lashed by straps 47 which are crisscrossed at the outer sides of said stirrups. With the limbs 43 and 45 thus extended, the sail 12 is held taut with the flyers head protruding beyond the leading edge 14, so that he may observe the space beneath the sail. Thus, it will be apparent that the size of the sail 12 will have to be varied to fit flyers of diiferent sizes.

The four edges 14-17 are inwardly bowed to insure that the outward force exerted on the corners of the sail by the hands and feet will be evenly distributed along said edges, to maintain the sail normally taut and bowed downwardly toward its center by the weight of the flyers body resting thereon. The openings 36 are provided to prevent fluttering of the sail adjacent its leading edge 14.

The flyers center of gravity during normal flight is slightly forward of the center of the sail 12. Normal flight is considered to constitute a neutral position of the sail and flyer, as illustrated in FIGURE 1, which creates just suflicient dihedral of the side portions of the sail, which are located between the flyers body and the side edges 16 and 17, to maintain its stability, with the sail maintained taut to minimize drag and so that there is neither change in turning tendency nor change in glide angle.

To dive, the legs are moved downwardly until the desired angle of the dive is obtained, whereupon the legs are returned to a neutral position. To decrease the angle of glide or dive, or to climb momentarily, the legs are moved upward until the desired angle of the sail is obtained, after which the legs are returned to a neutral position. A turn is accomplished by flexing an arm or leg to slacken one side edge to thereby momentarily decrease lift and increase drag of the sail portion located adjacent the slackened edge to effect a banked turn with the slacked edge on the inside of the turn. A turn may also be accomplished by dropping one leg and raising the other to deflect the passing air stream laterally to one side of the sail to induce rotation of the sail about its vertical axis; or this may be coupled with slackening of a side edge to effect a turn.

Various modifications and changes are contemplated and may be resorted to without departing from the function or scope of the invention, as hereinafter defined by the appended claims.

I claim as my invention:

1. A gliding sail for supporting a flyer in flight through the air comprising, a rectangular sheet of flexible material having a leading edge, a trailing edge and side edges, said sail having forward corners adapted to be grasped by the hands of the flyer with the arms extended outwardly and forwardly and rear corners adapted to be engaged by the feet of the flyer with the legs extended and spread, and said sail being of a length and width such that the sail will be held taut by the tensile strains exerted against the corners thereof by the hands and feet, said leading edge being inwardly bowed sufliciently so that the head of the flyer will be disposed therebeyond, said sail including a strong flexible line extending around said sheet and secured to each of the edges thereof.

2. A gliding sail for supporting a flyer in flight through the air comprising, a rectangular sheet of flexible material having a leading edge, a trailing edge and side edges, said sail having forward corners adapted to be grasped by the hands of the flyer with the arms extended outwardly and forwardly and rear corners adapted to be engaged by the feet of the flyer with the legs extended and spread, and said sail being of a length and width .4 such that the sail will be held taut by the tensile strains exerted against the corners thereof by the hands and feet, said sail including a strong flexible line extending around said sheet and secured to each of the edges thereof, said sheet having recessed corners, said line having slack portions disposed across each of said recessed corners, handholds secured to the slack portion of the front corners and adapted to be gripped by the hands, and stirrups secured to the slack portions of the rear corners and adapted to be secured to the feet.

3. A gliding sail as in claim 2, the leading edge, trailing edge and side edges of the sail being inwardly bowed between the corners thereof.

4. A gliding sail for supporting a flyer in flight through the air comprising, a rectangular sheet of flexible material having a leading edge, a trailing edge and side edges, said sail having forward corners adapted to be grasped by the hands of the flyer with the arms extended outwardly and forwardly and rear corners adapted to be engaged by the feet of the flyer with the legs extended and spread, and said sail being of a length and width such that the sail will be held taut by the tensile strains exerted against the corners thereof by the hands and feet, said sail having transversely spaced D-ring receiving openings through which D-rings on the front of a parachute harness extend for attachment to snap hooks of a reserve parachute for supporting the reserve parachute under the sail and for attaching the sail to the body of the flyer.

5. A gliding sail for supporting a flyer in flight through the air comprising, a rectangular sheet of flexible material having a leading edge, a trailing edge and side edges, said sail having forward corners adapted to be grasped by the hands of the flyer with the arms extended outwardly and forwardly and rear corners adapted to be engaged by the feet of the flyer with the legs extended and spread, and said sail being of a length and width such that the sail will be held taut by the tensile strains exerted against the corners thereof by the hands and feet, said leading edge being inwardly bowed sufliciently so that the head of the flyer will be disposed therebeyond, said sail being perforated adjacent its leading edge to prevent fluttering of the perforated portion of the sail.

References Cited by the Examiner UNITED STATES PATENTS 243,834 7/1881 Beeson 9-307 2,181,326 11/1939 Griffin 244-16 FOREIGN PATENTS 449,885 1/ 1913 France.

MILTON BUCHLER, Primary Examiner.

LARRY C. HALL, Examiner. A CORRIGAN, Assistant Examiner, 

1. A GLIDING SAIL FOR SUPPORTING A FLYER IN FLIGHT THROUGH HAVING AIR COMPRISING, A RECTANGULAR SHEET OF FLEXIBLE MATERIAL HAVING A LEADING EDGE, A TRAILING EDGE AND SIDE EDGES, SAID SAIL HAVING FORWARD CORNERS ADAPTED TO BE GRASPED BY THE HANDS OF THE FLYER WITH THE ARMS EXTENDED OUTWARDLY AND FORWARDLY AND REAR CORNERS ADAPTED TO BE ENGAGED BY THE FEET OF THE FLYER WITH THE LEGS EXTENDED AND SPREAD, AND SAID SAIL BEING OF A LENGTH AND WIDTH SUCH THAT THE SAIL WILL BE HELD TAUT BY THE TENSILE STRAINS EXERTED AGAINST THE CORNERS THEREOF BY THE HANDS AND FEET, SAID LEADING EDGE BEING INWARDLY BOWED SUFFICIENTLY SO THAT THE HEAD OF THE FLYER WILL BE DISPOSED THEREBEYOND, SAID SAIL INCLUDING A STRONG FLEXIBLE LINE EXTENDING AROUND SAID SHEET AND SECURED TO EACH OF THE EDGES THEREOF. 